(i) Field of the Invention
This invention relates to a method and apparatus for use in cleaning oil spills. It is particularly related to separating the oil from water preparatory to the cleaning up of the oil spill.
(ii) Description of the Prior Art
The widely known and contentious problem of cleaning up an oil spill in a harbour or elsewhere has resulted in the development of a number of devices, many of which have not proven to be too effective. Water-borne oil is a difficult substance to contain and pick up. Conventional mechanisms developed for this purpose, e.g., rotating conveyors equipped with belts of fabric and lengthy floating booms capable of sweeping the water surface, have many disadvantages.
When oil is spilled into a harbour or other body of water, the most immediate problem is to contain the oil so that it will not spread to such an extent that it is not practical or worthwhile even to try to remove the spillage. Sometimes a floating boom is used in an attempt to stop the spread of such water-borne oil but the shear physical task of assembling a lengthy boom as is normally required, and of the maneuvering the boom into a position where it might be effective, results in a delay which can render the whole exercise futile. Furthermore, a boom can only be successfully employed when water conditions are ideal which seldom is the case.
The use of ultrasonic or acoustical energy for the purpose of breaking up an oil spill has been proposed in the patent literature. Thus, Canadian Patent No. 1,065,768, patented Nov. 6, 1979 by J. N. Koblanski provided a purported solution to the problem by using acoustic waves to develop the force needed to separate the oil from the water. That patentee provided apparatus for removing from the surface of a body of water by means of a transducer, with means for supporting the transducer immersed in water. Electrical means were provided for energizing the transducer to generate sound waves. Focusing means were provided which were constructed and arranged to provide a region of focus for the sound waves located generally above the focusing means. Collecting means supported by the supporting means were constructed and arranged to collect oil removed from the surface of the body of water in the approximate area of the region of focus.
Another purported solution was said to be provided in Canadian Patent No. 1,067,709 patented Dec. 11, 1979 by J. N. Koblanski. That patentee contemplated the use of acoustical energy to provide, in effect, a huge broom which can be wielded to sweep floating oil into a confined area from where it can more readily be picked up by other means. More specifically, such apparatus included a sound-producing device having a member capable of transmitting a shaped and intensified ray of vibrational energy. Support means supported the device, e.g., below the water surface, in a position to direct the ray of vibrational energy upwardly towards the floating oil at a selected grazing angle relative to the water surface. Means were provided for activating the sound producing device to generate the ray of vibrational energy and to produce a horizontally-elongated and vertically-flattened zone of vibrational energy capable of exerting a propelling force on the floating oil.
U.S. Pat. No. 4,126,547 patented Nov. 12, 1978 by A. Kuris provided an apparatus by means of which oil slicks on surface waters were dispersed by the exposure of the surface oils to ultrasonic energy to effectuate an homogenization of the oil and water to permit absorption of the oil within the total volume of water. In accordance with the patented invention, a device for homogenization of the oil into the body of water was obtained using an output radiator or ultrasonic motor for generating longitudinal vibrations of large displacement amplitude adapted to produce periodic perturbations in the oil, and reflecting means disposable in facing relation to the generating means, i.e., the output radiator. The oil to be dispersed was funnelled through the gap between the ultrasonic motor and the reflecting means for reflecting the vibrations back into the fluid medium consisting of the oil layer and water. The reflecting surface was spaced from the generating means output surface a distance such that the reflected vibrations were substantially in phase with the vibrations radiated into the fluid medium by the output radiator. In this manner, the displacement amplitude of the fluid medium perturbations were said to be increased for the release of oil particles into the fluid primarily by the selective entrainment characteristics of the viscous forces generated by the perturbating medium.
U.S. Pat. No. 4,222,868 patented Sep. 16, 1980 by A. Kuris provided a method for cleaning the oil slick wherein the oil slick was carried through a fluid medium with longitudinal vibrations of large displacement amplitude being applied to the fluid medium from one side of the oil slick to reduce the viscosity thereof. The vibrations were reflected at, or somewhat beyond, the other side of the oil slick back into the fluid medium with the reflected vibrations being substantially in phase with the applied longitudinal vibrations, thereby substantially increasing the displacement amplitude of the fluid medium perturbations. The frequency of the vibrations and the viscosity of the fluid were coordinately selected for the release of particles from the oil slick into the body of water primarily by the selective entrainment characteristics of the forces generated by the perturbating medium.